Japanese. One of the main Asian languages, Japanese has a well-established system of transliteration into English. In most everyday writing, the accents that appear in some Japanese words are not used. Consult relevant reference works for details.
Jargon. A specialized vocabulary that is used mainly by a limited group of people in the same work or profession is called jargon. Since the meaning of jargon is known only to a restricted audience, its use limits the number of people who can understand what you are saying or writing. Such a limitation is not a problem if you are addressing only colleagues, professional associates, or peers; indeed, it can be a benefit since jargon is often shorthand that lets someone in the know quickly understand what you are trying to say. Jargon conveys information quickly about one’s knowledge, status, and membership in groups. But for more general audiences or those who might not be among the initiated in special usages of words, stick to more commonly recognized terminology.
Jargon: “How many megabytes in your box?” Translated: “Does your computer have lots of memory?” Even the second, translated example might be too obscure for those who are not computer literate. A better, but longer, question for them might be: “Does your computer have a large additional storage device to permanently record files?”
Jargon need not be technical. Many people speak in special ways among friends, neighbors, or others with whom they can identify by some means or other. Such language is also called “argot,” “lingo,” or “slang.” As it becomes more commonly recognized, it merges with colloquial, or everyday, speech and sometimes passes into accepted usage.
Jr. The abbreviation of “junior,” used very often with a comma after appropriate names (“Adam Arkin, Jr.”), but it’s never acceptable as an independent element in a sentence.